JPH06158251A - Method and apparatus for continuous annealing in plastic working - Google Patents

Abstract

PURPOSE:To execute the suitable annealing and wire drawing in good productivity by rapidly cooling an alloy annealed in high annealing temp. range to make equilibrium multi-phase structure, plastic working at the cold working temp. in the specific reducing surface area ratio and annealing in the low annealing temp. range. CONSTITUTION:After applying the ordinary plastic working to the alloy (e.g. 65/35 brass, etc.) having the equilibrium multi-phase structure in the high annealing temp. range and equilibrium single-phase structure in the low annealing temp. range, the ordinary annealing in the high annealing temp. range (primary annealing part) is applied to this alloy to form the equilibrium multi- phase structure and this alloy is rapidly cooled. In order to give strain energy to this alloy after annealing, one or plural times of the annealings are executed in the low annealing temp. range (secondary annealing part). By this method the alloy having the single phase structure is obtd. by the annealing for a short time and the manufacturing efficiency is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alloy annealing method and apparatus.

[0002]

2. Description of the Related Art Alloys such as 65/35 brass are made into final product dimensions by repeatedly subjecting an ingot made by melt casting to plastic working and annealing. The reason for annealing is that the alloy undergoes work hardening during plastic working and becomes unworkable at the end, so that the plastic working strain received by the alloy by intermediate annealing is released. Therefore, the larger the area reduction rate (cross-sectional area reduction rate) that can be plastically processed, the smaller the number of times of annealing.
This reduction in area can generally be made larger when the metallographic structure has a single phase rather than multiphase. However, depending on the annealing temperature, multiple phases may appear or a single phase may appear. For example, 65/35
The normal annealing temperature of brass is about 430 to 705 ° C., and at about 600 ° C. or higher, it is an α + β equilibrium two-phase structure, and at lower temperatures, it has an α single phase parallel structure. 0.2 ~
A wire having a large workability (area reduction rate of 90 to 95%) such as a wire cutting 65/35 brass electrode wire having a diameter of 0.3 mm is usually processed in a single-phase structure state.

In general, in order to shorten the annealing time, high temperature annealing is generally carried out within a range that does not impair mechanical properties such as tensile strength and elongation, thereby improving the production efficiency. However, when the equilibrium phase at the annealing temperature is multiphase, since the phase change does not occur sufficiently during cooling after annealing, the high temperature stable phase remains and becomes an unbalanced multiphase structure even at low temperatures. I will end up. Therefore, in order to obtain a sufficiently softened single-phase structure, it is necessary to anneal for a long time in a low-temperature equilibrium single-phase structure temperature range, but low-temperature annealing has poor production efficiency. In order to increase the production efficiency by low temperature continuous annealing, an annealing furnace with a large heating section is required, and especially when the material cannot be bent, the heating section becomes extremely long and requires a large installation area. Further, in the case of annealing a wide variety of small-quantity-produced materials, if an annealing furnace having a large heating section is used, there is a drawback that more annealing than necessary must be performed at once. For this reason, a method is adopted in which annealing is performed in a batch system, and the annealed material is stored and taken out each time a wire drawing operation is performed, and a continuous annealing device is not used.
The "low temperature" and "high temperature" used in this specification are relative ones.

[0004]

DISCLOSURE OF THE INVENTION An object of the present invention is to make an alloy having an equilibrium multiphase structure in a high temperature annealing temperature region and an equilibrium single phase structure in a low temperature annealing temperature region into a single phase structure by a short time annealing. By doing so, it is possible to increase the area reduction rate in plastic working, as a result it is possible to reduce the number of times of annealing, and to provide a continuous annealing method and apparatus capable of improving production efficiency regardless of the size of the lot to be annealed. That is.

[0005]

In order to achieve the above object, the annealing method of the present invention relates to an alloy having an equilibrium multiphase structure in a high temperature annealing temperature range and an equilibrium single phase structure in a low temperature annealing temperature range. The alloy having a non-equilibrium structure that has been annealed in the high temperature annealing temperature range is subjected to cold working with a surface reduction rate of 5 to 30% and then annealed for a short time in the low temperature annealing temperature range once or a plurality of times. Do it once.

In the above-mentioned annealing method of the present invention, in particular, alloy 6
It is most suitable when it is 5/35 brass.

Further, in the annealing method of the present invention, regarding an alloy having a balanced multiphase structure in a high temperature annealing temperature region and a balanced single phase structure in a low temperature annealing temperature region, a wire of the alloy is annealed for a short time. Means, followed by means for performing cold working, and subsequently means for performing short-time annealing in the low-temperature annealing region in succession, the means for performing the annealing being the length of the wire rod in the high-temperature annealing region. And a continuous annealing device characterized by having a device for controlling the length of the wire rod in the low temperature annealing region.

Further, in the continuous annealing apparatus, the means for performing the annealing has a pair of power feed wheels arranged so as to stretch the alloy wire, and a guide roll is provided between the pair of power feed wheels. It is also possible to control the length of the wire rod in the high temperature annealing region and the length of the wire rod in the low temperature annealing region by changing the positions of the guide rolls provided.

[0009]

The alloy to which the present invention can be applied can be applied to any alloy as long as the equilibrium structure in the high temperature annealing temperature region is multiphase and the equilibrium structure in the low temperature annealing temperature region is single phase, for example, 65/35.
Brass (including those added with Fe, Al, Ti, Cr, Zr, etc.), Ag-Al alloy, Ag-Cd alloy, Ag-Z
An n alloy, a Cu-Al alloy, etc. can be mentioned.

These alloys are normally annealed in the high temperature annealing temperature region (hereinafter referred to as primary annealing) after ordinary plastic working. When cold working is performed after the annealing, the structure of the alloy has a high temperature equilibrium phase. Presents residual tissue. The annealing may be performed by a batch furnace which is conventionally used or by continuous heating such as direct current heating. The alloy after annealing is subjected to cold working with a surface reduction rate of 5 to 30% in order to impart strain energy.
The cold working can be applied to any alloys such as wire drawing, rolling, swaging, etc. as long as they add working strain to the alloy.
Next, the alloy is annealed in the low temperature annealing temperature range for a short time (hereinafter referred to as secondary annealing). The short-time annealing method is preferably a rapid heating method such as direct current heating, infrared heating, laser heating, induction heating or heat roll heating. Since the alloy is subjected to work strain by the cold working, diffusion of alloy elements during the secondary annealing is accelerated more than when it is not subjected to work strain, and the equilibrium in the low temperature annealing temperature range is promptly reached. It has a single-phase structure and softens by annealing.

At this time, if the area reduction rate of the added cold working is less than 5%, the effect of promoting the diffusion of elements is insufficient, the structure is not sufficiently homogenized, and the multiphase structure remains. On the other hand, if the area reduction ratio exceeds 30%, recrystallization occurs before the diffusion of the contained element is sufficiently performed, strain energy is consumed, and the effect of promoting diffusion of the contained element is reduced, so that the structure is sufficiently homogenized. Instead, a multiphase structure remains. In order to accurately control the area reduction rate, it is important that the primary annealing is sufficiently softened and the strain energy is completely released.

The optimum secondary annealing conditions differ depending on the alloy type, alloy shape, and heating method, and the annealing temperature, annealing time, annealing speed, etc. may be set according to the required product characteristics. It is preferable that the heating condition is within a temperature range from just below the temperature at which a multiphase structure is formed to a temperature about 50 ° C. lower than that and about 2 seconds or less. Furthermore, when diffusion is insufficient in the above steps (primary annealing-cold working-secondary annealing) and the homogenization of the structure is insufficient, after the above steps, (cold working-secondary annealing The annealing process may be repeated.

Further, in the continuous annealing apparatus of the present invention, since the annealing region through which the wire passes is short, the wire can be annealed and drawn even if the wire to be processed at one time is relatively short, that is, even in a small lot. . That is, when the conventional low-temperature annealing method is continued as it is, the annealing region becomes long, so a wire rod having a length commensurate with it is required, whereas in the present invention, the annealing region is short, so the annealing is performed. Not only can the area occupied by the equipment be reduced, but it can also be used for processing small lots.

In the continuous device of the present invention, the winding of the wire is 1
It can be done with a take-up device on a stand, and productivity can be improved. When the wire is heated by energization, the heating is controlled by changing the distance between the power feed wheels.

[0015]

EXAMPLE A continuous annealing apparatus will be described in detail with reference to FIG.
The entire apparatus is placed at room temperature, and 1 is an alloy wire, which is continuously supplied through a fixed roll 2 in the order of a primary annealing part, a wire drawing part, and a secondary annealing part, and taken out through a fixed roll 3. 4, 5, 6, 7, 8, and 9 are power supply wheels, which are 4-5, 4
A voltage is applied between -6, 7-8, and 7-9, and an electric current is passed through the alloy wire rod 1 stretched between them. Guide roll 10
-12 and 13-15 can move their respective positions, change the length of the alloy wire rod 1 stretched between the feeding wheels 4-5 and 7-8, and change the electric resistance value between 4-5 and 7-8. By doing so, the preheating temperature of the alloy wire rod 1 is adjusted. The length of the alloy wire 1 stretched between the power feed wheels 4-5 and 7-8 of this embodiment is 3.5 m. The alloy wire is heated to the primary annealing temperature between the power feeding wheels 5-6 and to the secondary annealing temperature between the power feeding wheels 8-9. The length of the alloy wire 1 existing between the power feeding rolls 5-6 and 8-9 is about 1.5 m. In addition, back tension is not applied to the wire between the power feed wheels 5-6 and between the power feed wheels 8-9. In addition, in the continuous annealing apparatus of the present embodiment, the number of winding devices for the wire rod is one (not shown).

Numerals 16 to 17 are camp stuns of the alloy wire rod 1 which has been cooled after the primary annealing. The alloy wire rod 1 is cold worked by the wire drawing die 18 and wound on the camp stuns 19 to 20 and then the secondary annealing. Guided to the department.

FIG. 2 is an explanatory diagram of a power feeding diagram. 21-23
Is a power feeding brush made of copper alloy, which is in pressure contact with the power feeding wheels 4 to 6, and an alternating voltage is applied from the variable transformer 24. Also,
Voltage is also applied to the power supply wheels 7 to 9 through the same power supply brush as described above.

Further, in addition to this apparatus, it is also possible to use a power supply roll 25 which also serves as the power supply wheel 7 and the campstans 19 to 20 as shown in FIG. The power feeding wheel portion 7'and the camp stun portion 19 'are separated by an electric insulating material 26. The power may be supplied by an AC power supply or a DC power supply.

Next, the implementation numbers 1 to 5 will be described.

JIS C2700 equivalent alloy α + β 2
A 200 mm diameter billet produced by melting and casting phase brass was hot extruded at 800 ° C to form a wire having a diameter of 8 mm, and then cold drawn to form a wire rod having a diameter of 2.3 to 2.6 mm. The microstructure of this wire was two-phase. This wire rod is primary annealed by the above-mentioned continuous annealing device-cold working-
The secondary annealing was repeated 4 times. The total time required was 40 minutes. After that, 0.2-0.3mm by wire drawing
The wire material for wire cutting.

The primary annealing was performed under the conditions shown in Table 1. The wire feed rate is 200 to 450 m / min. The cold working was performed by cold drawing with a surface reduction rate of 2.3 to 52.1% shown in Table 2, and the secondary annealing was performed under the conditions shown in Table 1. Table 2 summarizes the amount of β phase present in the wire rod after the final secondary annealing, the mechanical properties, and the amount of treatment per hour.

[0022]

[Table 1]

[0023]

[Table 2]

According to this, no β phase was observed after secondary annealing in cold working Nos. 2 to 4 with a surface reduction rate of 5 to 30%, but in the other cold running Nos. 1 and 5, secondary phases were not observed. It can be seen that the β phase remains after annealing. Further, the scratches between the wire rods were extremely small in Run Nos. 2 to 4.

Implementation numbers 6 to 7 will be described. 2.6 mm diameter and 2.2 m diameter manufactured in the same manner as in Example No. 1.
The α + β brass wire of m was annealed at 460 ° C. for 2 hours in an atmospheric batch electric furnace, and a wire cutting wire having a thickness of 0.2 to 0.3 mm was obtained by wire drawing. Table 2 shows the β-phase amount, mechanical properties, and treatment amount of the wire rod after annealing. According to this, the β phase did not remain after annealing even in the execution numbers 6 to 7, but the annealing time is long. Therefore, it can be seen that the present invention has an annealing treatment amount that is about 3 to 4 times higher than that of Examples Nos. 6 and 7, and has excellent productivity.

From the above description, the continuous annealing method and apparatus for continuously performing the primary annealing, the cold working and the secondary annealing process not only improve the productivity, but also improve the productivity of each process. It can be seen that material scratches caused by rubbing can be eliminated.

Furthermore, since brass contains a large amount of zinc element which is easily oxidized, bright annealing cannot be performed in an inexpensive atmosphere such as water vapor which has a poor reducing ability as in the case of copper, but according to the present continuous annealing apparatus. Since the heating time is shortened, oxidation of the alloy is suppressed, and bright annealing can be performed in an atmosphere such as water vapor.

[0028]

The annealed alloy having the equilibrium multiphase structure in the high temperature annealing temperature range and the equilibrium single phase structure in the low temperature annealing temperature range is subjected to cold working at 5 to 30% and then to the low temperature. A single phase alloy is obtained by short time annealing in the zone. In addition, productivity can be increased by a continuous annealing device that continuously performs the above-mentioned primary annealing, cold working, and secondary annealing steps, material scratches that occur during each step can be eliminated, and oxidation of the alloy can be suppressed. Furthermore, even if the length of the wire to be treated is short, appropriate annealing /
Wire drawing can be performed.

[Brief description of drawings]

FIG. 1 is a flow chart of an alloy wire rod of a continuous annealing device according to an embodiment of the present invention.

FIG. 2 is a system diagram of a power supply system according to an embodiment of the present invention.

FIG. 3 is a conceptual diagram showing a structural example of a power feed wheel.

[Explanation of symbols]

 1 Alloy Wire 2, 3 Fixed Roll 4-9 Power Feed Wheel 7'Power Feed Wheel 10-15 Guide Roll 16, 17 Capstan 18 Wire Drawing Die 19-20 Capstan 19 'Capstan 21-21 Power Brush 24 Transformer 26 electrical insulation

Claims (4)

[Claims] 1. An alloy having an equilibrium multiphase structure in a high temperature annealing temperature range and an equilibrium single phase structure in a low temperature annealing temperature range, is annealed in the high temperature annealing temperature range to form an equilibrium multiphase structure, and is then rapidly cooled. , 5% to 30% reduction in area at cold working temperature
Of the plastic working, and then annealing in a low temperature annealing temperature range is performed once or a plurality of times. 2. The annealing method according to claim 1, wherein the alloy is 65/35 brass. 3. An alloy having an equilibrium multiphase structure in a high temperature annealing temperature range and an equilibrium single phase structure in a low temperature annealing temperature range, a wire rod of the alloy being annealed in the high temperature annealing temperature range, and subsequently. Means for performing cold working and a means for performing subsequent annealing in the low temperature annealing region in succession, and the means for performing the annealing is the length of the wire rod in the high temperature annealing region and the wire rod in the low temperature annealing region. A continuous annealing apparatus having a device for controlling the length of the. 4. The means for performing the annealing includes a pair of power supply wheels arranged so as to stretch the alloy wire.
4. A guide roll is provided between a pair of power feed wheels, and the length of the wire rod in the high temperature annealing region and the length of the wire rod in the low temperature annealing region are controlled by changing the position of the guide roll. The continuous annealing apparatus described in.